com.liferay.portal.kernel.security.SecureRandomUtil Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of com.liferay.portal.kernel Show documentation

Contains interfaces for the portal services. Interfaces are only loaded by the global class loader and are shared by all plugins.

There is a newer version: 156.0.0

Show newest version

/**
 * Copyright (c) 2000-present Liferay, Inc. All rights reserved.
 *
 * This library is free software; you can redistribute it and/or modify it under
 * the terms of the GNU Lesser General Public License as published by the Free
 * Software Foundation; either version 2.1 of the License, or (at your option)
 * any later version.
 *
 * This library is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
 * details.
 */

package com.liferay.portal.kernel.security;

import com.liferay.portal.kernel.io.BigEndianCodec;
import com.liferay.portal.kernel.util.GetterUtil;

import java.security.SecureRandom;

import java.util.Random;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.atomic.AtomicInteger;

/**
 * @author Shuyang Zhou
 */
public class SecureRandomUtil {

	public static boolean nextBoolean() {
		byte b = nextByte();

		if (b < 0) {
			return false;
		}
		else {
			return true;
		}
	}

	public static byte nextByte() {
		int index = _index.getAndIncrement();

		if (index < _BUFFER_SIZE) {
			return _bytes[index];
		}

		return (byte)_reload(index);
	}

	public static double nextDouble() {
		int index = _index.getAndAdd(8);

		if ((index + 7) < _BUFFER_SIZE) {
			return BigEndianCodec.getDouble(_bytes, index);
		}

		return Double.longBitsToDouble(_reload(index));
	}

	public static float nextFloat() {
		int index = _index.getAndAdd(4);

		if ((index + 3) < _BUFFER_SIZE) {
			return BigEndianCodec.getFloat(_bytes, index);
		}

		return Float.intBitsToFloat((int)_reload(index));
	}

	public static int nextInt() {
		int index = _index.getAndAdd(4);

		if ((index + 3) < _BUFFER_SIZE) {
			return BigEndianCodec.getInt(_bytes, index);
		}

		return (int)_reload(index);
	}

	public static long nextLong() {
		int index = _index.getAndAdd(8);

		if ((index + 7) < _BUFFER_SIZE) {
			return BigEndianCodec.getLong(_bytes, index);
		}

		return _reload(index);
	}

	private static long _reload(int index) {
		if (_reloadingFlag.compareAndSet(false, true)) {
			_random.nextBytes(_bytes);

			_gapRandom.setSeed(_random.nextLong());

			_index.set(0);

			_reloadingFlag.set(false);
		}

		return _gapRandom.nextLong() ^
			BigEndianCodec.getLong(
				_bytes, Math.abs(index % (_BUFFER_SIZE - 7)));
	}

	private static final int _BUFFER_SIZE;

	private static final int _MIN_BUFFER_SIZE = 1024;

	private static final byte[] _bytes;
	private static final Random _gapRandom = new Random();
	private static final AtomicInteger _index = new AtomicInteger();
	private static final Random _random = new SecureRandom();
	private static final AtomicBoolean _reloadingFlag = new AtomicBoolean();

	static {
		int bufferSize = GetterUtil.getInteger(
			System.getProperty(
				SecureRandomUtil.class.getName() + ".buffer.size"));

		if (bufferSize < _MIN_BUFFER_SIZE) {
			bufferSize = _MIN_BUFFER_SIZE;
		}

		_BUFFER_SIZE = bufferSize;

		_bytes = new byte[_BUFFER_SIZE];

		_random.nextBytes(_bytes);

		_gapRandom.setSeed(_random.nextLong());
	}

}